The Atrium in Atrial Fibrillation - A Clinical Review on How to Manage Atrial Fibrotic Substrates

Atrial fibrillation (AF) is the most common sustained arrhythmia in the population and is associated with a significant clinical and economic burden. Rigorous assessment of the presence and degree of an atrial arrhythmic substrate is essential for determining treatment options, predicting long-term success after catheter ablation, and as a substrate critical in the pathophysiology of atrial thrombogenesis. Catheter ablation of AF has developed into an essential rhythm-control strategy. Nowadays is one of the most common cardiac ablation procedures performed worldwide, with its success inversely related to the extent of atrial structural disease. Although atrial substrate evaluation remains complex, several diagnostic resources allow for a more comprehensive assessment and quantification of the extent of left atrial structural remodeling and the presence of atrial fibrosis. In this review, we summarize the current knowledge on the pathophysiology, etiology, and electrophysiological aspects of atrial substrates promoting the development of AF. We also describe the risk factors for its development and how to diagnose its presence using imaging, electrocardiograms, and electroanatomic voltage mapping. Finally, we discuss recent data regarding fibrosis biomarkers that could help diagnose atrial fibrotic substrates.info:eu-repo/semantics/publishedVersio

Can biofuel policies reduce uncertainty and increase agricultural yields through stimulating investments?

As history shows, the yield gap (the difference between actual and achievable yields) will not necessarily close automatically. Investments in agricultural technologies may be key. Price volatility is fundamental to investment. Price volatility has increased in agriculture in the past decade, leading to higher risks for potential investments. Some of these increased risks may be offset by the certainty offered by credible policies. The US experience indicates that ethanol policy may contribute to yield increases. Analysis suggests that corn use by ethanol plants in the USA may explain a significant part of the observed yield increase. A theoretical framework, centered on downside price-stabilization effects, is offered here, supported by some US, EU, and Hungarian empirical evidence. The research presented explores whether new ethanol plants resulting from effective biofuel policies could serve as a market mechanism to stimulate investments in farming technologies, triggering increased productivity. A survey of local stakeholders of an ethanol plant in Hungary, the only large-scale biofuel investment triggered in Europe by the EU’s flagship bioenergy policy (the Renewable Energy Directive) suggests that relevant investments may have been stimulated. Over half of the respondent farmers said that the presence of the ethanol plant had stimulated investments in productivity. It is proposed that ethanol or biofuel policies may be effective in closing the yield gap, in effect resulting in additional biomass production and advancing the bioeconomy. With effective cross-sectoral policies, more biomass for food, feed, bio-based materials and / or bioenergy purposes can be produced

Antiarrhythmic drugs for atrial fibrillation: lessons from the past and opportunities for the future.

Atrial fibrillation (AF) remains a highly prevalent and troublesome cardiac arrhythmia, associated with substantial morbidity and mortality. Restoration and maintenance of sinus rhythm (rhythm-control therapy) is an important element of AF management in symptomatic patients. Despite significant advances and increasing importance of catheter ablation, antiarrhythmic drugs (AADs) remain a cornerstone of rhythm-control therapy. During the past 50 years, experimental and clinical research has greatly increased our understanding of AADs. As part of the special issue on paradigm shifts in AF, this review summarizes important milestones in AAD research that have shaped their current role in AF management, including (i) awareness of the proarrhythmic potential of AADs; (ii) increasing understanding of the pleiotropic effects of AADs; (iii) the development of dronedarone; and (iv) the search for AF-specific AADs. Finally, we discuss short- and long-term opportunities for better AF management through advances in AAD therapy, including personalization of AAD therapy based on individual AF mechanisms

Optimal timing of harvest of two fish species with multiple gear types

In this paper a bioeconomic model is developed for a commercial fishery with multiple gear types in the case of two independent fish species. Where most bioeconomic fishery models focus on either multiple gear types or multiple species (mostly predator-prey relationships) this model combines both aspects for four gear types and two independent fish species. The objective of the paper is to find the optimal allocation of four gear types per period to obtain the highest net benefits while harvesting at a sustainable rate. This is done by developing a discrete time LP-model for a sole owner fishery, given a Total Allowable Catch for the two fish species. The model is applied to the Chippewas of Nawash First Nation commercial fishery in Lake Huron and Georgian Bay (Ontario, Canada). Sensitivity analyses are performed on price changes as well as on the average harvest levels per boat

Tecnologias digitais no processo de alfabetização: analisando o uso do laboratório de informática nos anos iniciais

Este artigo discute tecnologias digitais na alfabetização, onde os estudantes as utilizam para desenvolver seus conhecimentos. Iniciamos com breves considerações sobre o uso das tecnologias na educação e as implicações na alfabetização. Em seguida, apresentamos resultados de uma pesquisa qualitativa, realizada com 15 professores que atuam nas salas de aula de alfabetização de 1º e 2º anos do Ensino Fundamental e professores de laboratório de informática de seis escolas no Município de Curitiba – PR. O propósito deste estudo foi analisar e investigar o impacto do uso do laboratório de informática no processo de alfabetização dos educandos nos anos iniciais. Este trabalho de pesquisa junto aos professores alfabetizadores permitiu que se elencassem duas categorias de análise preliminar: Uso e Planejamento para o Laboratório de Informática; Contribuições para Aprendizagem e Alfabetização no Laboratório de Informática. As reflexões baseiam-se nos estudos de Almeida (2005; 1998); Kenski (2012), Leite, Colello e Arantes (2010), Lucena (2002), Masetto(2000), Moran (2007), Nóvoa (2010), Pretto (2000), Sancho e Hernandez (2006), Soares (2004; 1998), Valente (1999; 1998). O resultado apontou que os professores alfabetizadores utilizam o laboratório de informática nas práticas educativas e que há saberes e habilidades que os alfabetizandos adquirem fazendo uso deste ambiente como melhora na leitura e na oralidade,reconhecimento de letras, registro de letras, palavras e textos, coordenação motora, atenção, raciocínio e nas suas produções

Cumulative hydropathic topology of a voltage-gated sodium channel at atomic resolution

Voltage-gated sodium channels (NavChs) are biological pores that control the ow of sodium ions through the cell membrane. In humans, mutations in genes encoding NavChs can disrupt physiological cellular activity thus leading to a wide spectrum of diseases. Here, we present a topological connection between the functional architecture of a NavAb bacterial channel and accumulation of atomic hydropathicity around its pore. This connection is established via a scaling analysis methodology that elucidates how intrachannel hydropathic density variations translate into hydropathic dipole field configurations along the pore. Our findings suggest the existence of a non random cumulative hydropathic topology that is organized parallel to the membrane surface so that pore's stability, as well as, gating behavior are guaranteed. Given the biophysical significance of the hydropathic effect, our study seeks to provide a computational framework for studying cumulative hydropathic topological properties of NavChs and pore-forming proteins in general. This article is protected by copyright. All rights reserved